Air blowing device

ABSTRACT

An air blowing device including; a fan mounted on at least one of an upper part and a lower part of a shelf; a louver having a louver board that extends in a direction intersecting with a direction of plugging in of a plug-in unit; and a louver controller to control the direction of the louver board based on a change of the mounting status of plug-in units housed in the shelf.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2010-187934, filed on Aug. 25, 2010, the entire contents of which are incorporated herein by reference.

FIELD

The embodiments disclosed herein are related to an apparatus for cooling an electronic apparatus housed in a shelf.

BACKGROUND

So-called bookshelf-type apparatuses, where plug-in units (PIUs) are plugged in and pulled out of back wiring boards (BWBs), have been widely used for station apparatuses in optical communication networks. The book-shelf type apparatus includes a back wiring board mounted on a back board of a shelf in a housing made of metal or the like and houses plug-in units, which are attached to the back wiring board, in the shelf. In recent years, as disclosed in Japanese Laid-open Patent Publication No. 2008-047716, a shelf where half-sized plug-in units are aligned on two or more vertical stages and are plugged in and pulled out of the shelf has been predominantly used.

The plug-in unit is a board-type electronic apparatus where a printed circuit board on which an optical component and an integrated circuit are mounted is provided as a main component. The plug-in unit in the electronic apparatus in operation generates heat. The shelf is provided with an air blowing device composed of a fan and a louver, such as one disclosed in Japanese Laid-open Patent publication No. 2000-151165. In other words, the blower device ventilates the shelf by blowing air from the fan mounted on the lower or upper part of the shelf, while suitably controlling the ventilation state with the direction of a louver board of the louver.

SUMMARY

According to an aspect of the invention, an air blowing device is provided. The air blowing device includes a fan mounted on at least one of an upper part and a lower part of a shelf; a louver having a louver board that extends in a direction intersecting with a direction of plugging in of a plug-in unit; and a louver controller operable to control the direction of the louver board based on a change of the mounting status of plug-in units housed in the shelf.

The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view illustrating a shelf according to an embodiment;

FIG. 2 is a perspective view illustrating a state of half pulling out one of the plug-in units from the shelf illustrated in FIG. 1;

FIG. 3 is a perspective view illustrating a state in which the plug-in unit which was half pulled out of the shelf in FIG. 2 is completely removed;

FIG. 4A and FIG. 4B are diagrams each illustrating an air blowing device according to a first embodiment;

FIG. 5 is a diagram illustrating an exemplary configuration of the louver;

FIG. 6 is a diagram illustrating a case where the direction of a louver board is fixed;

FIG. 7 is a diagram illustrating a ventilation state upon unplugging the plug-in unit with respect to the air blowing device according to the first embodiment;

FIG. 8A and FIG. 8B are diagrams illustrating an air blowing device according to the second embodiment;

FIG. 9A and FIG. 9B are diagrams illustrating an air blowing device according to the third embodiment;

FIG. 10 is a diagram illustrating a case where the direction of a louver board is fixed;

FIG. 11 is a diagram illustrating a ventilation state upon unplugging the plug-in unit with respect to the air blowing device according to the third embodiment;

FIG. 12A and FIG. 12B are diagrams each illustrating an air blowing device according to a fourth embodiment;

FIG. 13 is a diagram illustrating a case where the direction of a louver board is fixed;

FIG. 14 is a diagram illustrating a ventilation state upon unplugging the plug-in unit with respect to the air blowing device according to the fourth embodiment;

FIG. 15 is a diagram illustrating a ventilation state upon unplugging the plug-in unit with respect to the air blowing device according to the related art;

FIG. 16 is a diagram illustrating a ventilation state upon unplugging the plug-in unit with respect to the air blowing device according to the fourth embodiment;

FIG. 17A and FIG. 17B are diagrams each illustrating a first exemplary configuration of a louver controller;

FIGS. 18A, 18B, and 18C are diagrams each illustrating a louver controller according to a first exemplary configuration;

FIGS. 19A, 19B, and 19C are diagrams each illustrating a louver controller according to a second exemplary configuration;

FIGS. 20A, 20B, and 20C are diagrams each illustrating a louver controller according to a third exemplary configuration; and

FIG. 21 is a diagram illustrating a louver controller according to a fourth exemplary configuration.

DESCRIPTION OF EMBODIMENTS

A ventilation state in a shelf by an air blowing device becomes increasingly important in proportion with increases in packaging density and power consumption of a plug-in unit along with an increase in communication capacity. For example, in a shelf in which half-sized plug-in units are housed in two upper and lower stages, it can be assumed that any one of the plug-in units housed in the lower stage may be pulled out for replacement or the like. In the shelf under this situation, an empty slot after unplugging the plug-in unit serves as an opening for allowing an airflow caused by an air blowing device to leave the inside of the shelf. For this reason, when the air blowing device is arranged so that device sends air from the lower side to the upper side of the shelf, part of the air heading to the upper stage through the lower-stage plug-in units escapes to the outside through the empty slot, which may be created by removal of the plug-in unit. Thus, the amount of air passing through the upper-plug-in units decreases compared with the amount before unplugging of the plug-in unit. As a result, increases in temperatures of the plug-in units housed in the upper stage may occur.

A decrease in amount of ventilation may quickly cause an increase in temperature of one or more of the remaining plug-in units. In the case of the plug-in unit used in an optical communication apparatus, the temperature may reach the upper limit of an operation-ensuring temperature within about three minutes, for example. In this case, the time until the plug-in unit is reinserted after being unplugged, or a duration time of the presence of an empty slot should be not longer than about three minutes. The duration time for allowing the presence of the empty slot has been shortened down to about one minute in the case of the latest plug-in unit having higher power consumption and packaging density of circuit elements. In other words, it is becoming difficult to ensure a permissible time for the replacement or check of a plug-in unit.

FIGS. 1 to 3 are schematic diagrams illustrating plugging in/pulling out a plug-in unit in an optical communication apparatus. Hereinafter, a case where plug-in units are set up in two upper and lower stages and housed in one shelf will be described. An embodiment described below is also applicable to a case in which plug-in units are set up in three or more stages and housed in one shelf.

A shelf 101 illustrated in FIGS. 1 to 3 is, for example, a metal housing with a back plate portion on which a back wiring board 102 is mounted. A plurality of plug-in units is plugged in and pulled out of the back wiring board 102. In the illustrated shelf 101, half-sized plug-in units 105 and 106 are lined up and housed in two upper and lower stages. The plug-in units 105 in the upper stage and the plug-in units 106 in the lower stage are connected to optical fiber cables, respectively. Filler panels 108 are attached when the plug-in units 105 and 106 are not inserted. Thus, the leakage of wind (i.e., airflow) from the front of the shelf is reduced and/or prevented. The filler panel 108 may be a dummy plug-in unit that imitates the appearance of the plug-in unit. The shelf 101 may house a full-sized plug-in unit 110. When the full-sized plug-in unit 110 is not inserted, a filler panel 108 which may be a dummy plug-in unit corresponding to the full-sized plug-in unit 110 may be attached.

As illustrated in FIG. 2 and FIG. 3, the plug-in units 105, 106, and 110 may be plugged in and pulled out of slots one by one. After unplugging the plug-in units 105, 106, and 110, the slots become empty.

A top panel 112 of the upper portion of the shelf 101 inclines obliquely upward toward the back wiring board 102 and serves as a baffle part for sending out wind. Furthermore, a fan 1 and a louver 2, which are included in an air blowing device as illustrated in FIG. 4A and FIG. 4B, are installed in a bottom panel 116, the lower part of the shelf 101. FIG. 4A is a schematic diagram viewed from the front side of the shelf 101, and FIG. 4B is a schematic diagram viewed the right side of the shelf 101.

The air blowing device of FIGS. 4A and 4B are push types where the fans 1 are installed on the lower part of the shelf 101. The push type refers to a system where a fan works to introduce air outside the shelf into the inside of the shelf. In contrast, a pull type refers to a system where a fan works to remove air from inside the shelf to the outside of the shelf.

For example, four fans 1 are arranged in line in the direction Y (or horizontal direction) intersecting the direction X of plugging in/pulling out the plug-in units 105 and 106 (or depth direction), and two fans 1 arranged in line in the plugging in/pulling out direction X. Furthermore, the louver 2 for controlling the direction of air (flow of air) is placed above the fans 1.

For example, the louver 2 includes four louver boards 2 a corresponding to the width of the device. These louver boards 2 a are arranged in line and substantially parallel to one another in the plugging in/pulling out direction X and extending in the intersecting direction Y. The direction of wind flowing in the shelf 101 is adjusted by controlling the direction of the louver board 2 a of the louver 2 placed between the fans 1 and the lower-stage plug-in unit 106. The air blowing device illustrated in FIGS. 4A and 4B further includes wind speed sensors 3 placed at positions corresponding to the respective slots of the plug-in units 105 and 106. The wind speed sensors 3 illustrated in FIGS. 4A and 4B are placed on the upper part of the shelf 101, or the inside of the baffle part of the top panel 112, at a position at which a decrease in wind speed may significantly occur after removal of the plug-in unit 106 in the lower stage and a remarkable decrease in wind speed may be recognized without depending on the wind direction of the louver 2.

FIG. 5 is a perspective diagram illustrating an exemplary configuration of the louver 2. The louver boards 2 a of the louver 2 have rotation axes 2 b protruding from the opposite end surfaces thereof, respectively. The rotation axes 2 b are supported by axis bearings formed on side plates 114 of the shelf 101, respectively. Thus, each louver board 2 a is rotatably attached to the side plate 114. As a control unit for the louver 2, a pinion gear 2 c is formed around the periphery of the rotation axis 2 b and the pinion gears 2 c are geared with a single common rack gear 2 d. The rack gear 2 d is driven by a motor 2 e. By controlling the rotation of the motor 2 e, the directions of four louver boards 2 a are collectively controlled through the rack and pinion gears 2 c and 2 d. The number of the louver boards 2 a may be one at minimum as long as the direction of wind is changeable. For example, only one louver 2 may be mounted in the horizontal direction of the shelf. Alternatively, more than one louver 2 may be mounted in the horizontal direction of the shelf 101.

For example, two or more louvers 2 may be mounted so as to correspond to the respective slots in the horizontal direction of the shelf. In the example illustrated in FIG. 4A, the shelf has eight slots in the horizontal direction. Thus, the number of the louvers 2 may be eight corresponding to these slots.

The shelf 101 illustrated in FIGS. 4A and 4B is in a usual state referred to herein as a state in which all the plug-in units 105 and 106 (and/or filler panels 108) are housed. In this usual state, the directions of the louver boards 2 a of the louver 2 in the air blowing device are kept in usual directions. The usual directions of the louver boards 2 a of the louver 2 herein is a state in which the inside of the shelf 101 is in the optimum ventilation state. As illustrated in FIG. 4B, the top plate 112 of the shelf 101 is formed as an inclined baffle part. Therefore, in consideration of air flow sent out from the baffle part to the interior in the depth direction, the usual directions of the respective louver boards 2 a are inclined to the front side of the shelf 101 in the depth direction thereof, or inclined in the direction of introducing wind from the fans 1 to the side opposite to the back wiring board 102.

Hereinafter, the control of the direction of the louver board 2 a when one of the plug-in units 106 in the lower stage is unplugged (e.g., removed) from the usual state illustrated in FIGS. 4A and 4B will be described.

FIG. 6 is a diagram illustrating a case where the directions of the respective louver boards 2 a are fixed. FIG. 7 is a diagram illustrating the air blowing device according to the first embodiment.

First, in the case of FIG. 6, the louver boards 2 a are kept in usual directions and left in the same directions even if the plug-in units 105 and 106 are unplugged. In the case of FIG. 6, as described above, the louver 2 with the louver boards 2 a in the usual direction directs the direction of ventilation by the fans 1 toward the front side of the shelf 101. Therefore, when the plug-in unit 106 in the lower stage is unplugged, an empty slot after unplugging becomes an escape path of the wind. Therefore, as represented by the dashed arrows in FIG. 6, a large amount of wind escaping from the empty slot to the outside of the shelf 101 occurs. Thus, the amount of wind passing through the empty slot through the lower-stage plug-in unit 106 and heading toward the upper-stage plug-in unit 105 decreases. There is a disadvantage in that a decrease in the amount of wind may occur in the upper stage plug-in unit 105.

Next, in the case of the air blowing device of the first embodiment illustrated in FIG. 7, the directions of the louver boards 2 a in the louver 2 are changed from the usual state when at least one of the plug-in units 106 is pulled out of the lower stage. In other words, when the plug-in unit 106 is unplugged, the directions of the respective louver boards 2 a are changed so that the direction of ventilation by the fans 1 is changed to reduce the amount of wind leaving the shelf 101 through the empty slot after unplugging. In the case of FIG. 7, the direction of ventilation by the fans 1, which causes a decrease in amount of wind leaving the shelf 101, is a direction opposite to the usual direction of the louver boards 2 a. In other words, the direction of louver boards 2 a is controlled so that the air is directed toward the direction of the back wiring board 102 in the interior of the shelf 101. Then, as illustrated in FIG. 7, the louver boards 2 a of the louver 2 are controlled so that they direct the air to a direction different to the usual direction and are inclined toward the interior of the shelf 101.

By changing the direction of the louver board 2 a, as illustrated by the dotted arrows in FIG. 7, the wind generated by the fans 1 blows in the direction opposite to the opening of the front side formed by the empty slot. Therefore, compared to the case of FIG. 6, the amount of wind leaving the shelf 101 from the empty slot is reduced. As a result, compared to the case in FIG. 6, the amount of wind passing through the plug-in units 106 in the lower stage and heading to the plug-in units 105 in the upper stage increases. Therefore, the slope of thermal elevation in the plug-in unit 105 in the upper stage is reduced, so that a duration time of a state where the slot is being emptied may be prolonged. Furthermore, in the first embodiment, there is no substantial influence on the amount of wind passing through the plug-in unit 106 in the lower stage when the plug-in unit 105 is pulled out of the upper stage. Rather, since ventilation resistance due to the presence of the plug-in unit 105 in the upper stage disappears, the amount of wind passing through the plug-in units 106 in the lower stage becomes favorable. Therefore, although the control of direction of the louver 2 may be made unnecessary, the direction of the louver 2 may be controlled in a manner similar to the case illustrated in FIG. 7.

FIGS. 8A and 8B are diagrams each illustrating an air flow device according to a second embodiment.

A shelf 801 illustrated in FIGS. 8A and 8B is different from the one in the first embodiment. The top plate 112 a of the shelf 801 is of a ventilated type, for example a lattice-shaped top plate. Thus, the shelf 801 is constructed so that wind passing through the upper-stage plug-in units 105 goes straight and escapes upward. Like the case of FIGS. 4A and 4B, fans 1 and a louver 2 of the air blowing device are installed in the lower part of the shelf 801. The usual directions of the louver boards 2 a in the louver 2 illustrated in FIG. 8A are those that optimize the ventilation state in the shelf 801. In other words, as illustrated in FIG. 8A, the direction of the louver board 2 a is set in the vertical direction without inclination to allow wind from the fans 1 to move directly upward.

When all the plug-in units 105 and 106 (and/or filler panels 108) are housed in the shelf 801 and at least one of the plug-in units 106 is then pulled out of the lower stage, the direction of each louver board 2 a is changed from the usual direction in the louver 2 as illustrated in FIG. 8B. In other words, the directions of the louver boards 2 a in the louver 2 are controlled so that the amount of wind, which is generated by the fans 1 and blows out of the shelf 801 from the empty slot after unplugging, is reduced. In other words, as in the case with FIG. 7, the direction of the louver board 2 a is controlled so that the direction is directed toward the back wiring board 102. By changing the direction of the louver board 2 a, as illustrated by the dashed arrows in FIG. 8B, the wind generated by the fans 1 blows in the direction opposite to the outlet of the empty slot. Therefore, the amount of wind leaving the shelf 801 is reduced. As a result, the amount of wind passing through between the plug-in units 106 in the lower stage and heading to the plug-in units 105 in the upper stage increases. Therefore, the slope of thermal elevation in the plug-in unit 105 in the upper stage becomes decreases so that a duration time of a state where the slot is being emptied may be prolonged.

FIGS. 9A and 9B are diagrams each illustrating an air blowing device according to a third embodiment.

A shelf 901 illustrated in FIGS. 9A and 9B has a bottom plate 116 a of a ventilated type, such as a lattice-shaped bottom plate, from which wind is drawn into the shelf 901. Fans 1 and a louver 2 of the air blowing device are installed in the top plate 112 b in the top part of the shelf 901. Like FIGS. 4A and 4B, FIG. 9A is a schematic diagram viewed from the front side of the shelf 901, and FIG. 9B is a schematic diagram viewed from the right side of the shelf 901.

The air blowing device of FIGS. 9A and 9B is a pull type where the fans 1 are installed on the upper part of the shelf 901. For example, four fans 1 are arranged in line in the direction Y intersecting the direction X of plugging in/pulling out the plug-in units 105 and 106, and two fans 1 are arranged in line in the plugging in/pulling out direction X.

Furthermore, the louver 2 for controlling the direction of wind (flow of air) is placed below the fans 1. In the louver 2, four louver boards 2 a corresponding to the width of the device are arranged in line and substantially parallel to one another in the plugging in/pulling out direction X and extending in the intersecting direction Y. The direction of wind flowing in the shelf 901 is adjusted by controlling the direction of the louver boards 2 a of the louver 2 placed between the fans 1 and the upper-stage plug-in unit 105.

The air blowing device illustrated in FIGS. 9A and 9B further includes wind speed sensors 3 placed at positions corresponding to the respective slots of the plug-in units 105 and 106. The wind speed sensors 3 illustrated in FIGS. 9A and 9B are placed on the lower part of the shelf 101, or the bottom panel 116, at a position at which a decrease in wind speed may significantly occur after removal of the plug-in unit 105 in the upper stage and a remarkable decrease in wind speed may be recognized without depending on the wind direction of the louver 2.

The shelf 901 illustrated in FIGS. 9A and 9B is in a usual state where all the plug-in units 105 and 106 (and/or filler panels 108) are housed. In this usual state, the directions of the louver boards 2 a of the louver 2 in the air blowing device are kept in usual directions so that the inside of the shelf 901 is in the optimum ventilation state. As illustrated in FIG. 9B, the usual direction of the louver board 2 a in the louver 2 is set in the vertical direction without inclination to allow wind from the fans 1 to move directly upward.

Hereinafter, the control of the direction of the louver boards 2 a when one of the upper stage plug-in units 105 is unplugged from the usual state illustrated in FIGS. 9A and 9B will be described. FIG. 10 is a diagram illustrating a case where the directions of the respective louver boards 2 a are fixed. FIG. 11 is a diagram illustrating the air blowing device according to the third embodiment.

In the case of FIG. 10, the louver boards 2 a are kept in usual directions and left in the same directions even if the plug-in units 105 and 106 are unplugged.

In the case of FIG. 10, when the plug-in unit 105 in the upper stage is pulled out, an empty slot after removal of the plug-in unit 105 becomes a path for the wind to enter the shelf 901. Thus, as illustrated by the dashed arrows in FIG. 10, wind introduced by the fans 1 enters from the outside of the shelf 901 through the empty slot. As a result, the amount of wind passing between the plug-in units 106 in the lower stage and heading to the plug-in units 105 in the upper stage decreases. There is a disadvantage in that a decrease in the amount of wind may occur in the lower stage plug-in unit 106.

In the case of the air blowing device of the third embodiment illustrated in FIG. 11, the directions of the louver boards 2 a in the louver 2 are changed from the usual state when at least one of the upper stage plug-in units 105 is pulled out of the upper stage. In other words, when the plug-in unit 105 is unplugged, the directions of the respective louver boards 2 a are changed so that the direction of ventilation by the fans 1 is changed to reduce the amount of wind entering the shelf 901 through the empty slot after unplugging.

In the case of FIG. 11, the direction along which the amount of wind entering the shelf 901 through the empty slot is a direction along which the amount of wind drawn by the fans 1 from the vicinity of the back wiring board 102 in the interior of the shelf 901 increases. In other words, as illustrated in FIG. 11, the directions of louver boards 2 a in the louver 2 are changed to those inclined toward the interior of the shelf 901.

By changing the direction of the louver boards 2 a in the louver 2, as illustrated by the dashed arrows in FIG. 11, the wind generated by the fans 1 is in the direction drawing away from the empty slot in the shelf 901. Compared to the case of FIG. 10, the amount of wind entering the shelf 901 through the empty slot is reduced. As a result, compared to the case in FIG. 10, the amount of wind passing through the plug-in units 106 in the lower stage and heading to the plug-in units 105 in the upper stage increases. Therefore, the slope of thermal elevation in the plug-in unit 106 in the lower stage is reduced, so that a duration time of a state where the slot is being emptied may be prolonged. Furthermore, in the third embodiment, there is no substantial influence on the amount of wind passing through the plug units 105 in the upper stage when the plug-in unit 106 is pulled out of the lower stage. Rather, since ventilation resistance due to the presence of the plug-in unit 106 in the lower stage disappears and the wind is drawn from the empty slot, the amount of wind passing through the plug-in units 105 in the upper stage becomes favorable. Although the control of direction of the louver 2 may be made unnecessary, the direction of the louver 2 may be controlled similarly.

FIGS. 12A and 12B are diagrams each illustrating an air blowing device according to a fourth embodiment.

A shelf 1201 illustrated in FIGS. 12A and 12B has a top plate 112 c of a ventilation type, such as a lattice-shaped top plate, from which wind blows out upward. Fans 1 and a louver 2 of the air blowing device are installed in the bottom plate 116 of the bottom part of the shelf 1201. In FIGS. 12A and 12B, second louvers 2′ are arranged on the top plate 112 c on the upper part of the shelf 1201. Thus, the louvers 2 and 2′, which can control the direction of wind, are installed on the upper and lower parts of the shelf 1201, respectively. Like FIGS. 4A and 4B, FIG. 12A is a schematic diagram viewed from the front side of the shelf 1201, and FIG. 12B is a schematic diagram viewed the right side of the shelf 1201.

The air blowing device of FIGS. 12A and 12B is a push type where the fans 1 are installed on the lower part of the shelf 1201. For example, four fans 1 are arranged in line in the direction Y intersecting the direction X of plugging in/pulling out the plug-in units 105 and 106 and two fans 1 arranged in line in the plugging in/pulling out direction X. Furthermore, the louver 2 for controlling the direction of wind is placed above the fans 1. In the louver 2, four louver boards 2 a corresponding to the width of the device are arranged in line and substantially parallel to one another in the plugging in/pulling out direction X and extending in the intersecting direction Y. Furthermore, in the air blowing device illustrated in FIGS. 12A and 12B, a louver 2′ for controlling the direction of wind is also placed on the upper part of the shelf 1201. For example, the louver 2′ may have the same structure as that of the louver 2 and may include four louver boards 2′a corresponding to the width of the device and extending in the intersection direction Y and being arranged substantially parallel with one another in the plugging in/pulling out direction X. The louver 2 placed between the fans 1 and the lower stage plug-in unit 106 and the louver 2′ placed above the plug-in unit 105 cooperate to control the direction of wind, thereby controlling the direction of wind blown by the fans 1. The air blowing device illustrated in FIGS. 12A and 12B further includes wind speed sensors 3 placed at positions corresponding to the respective slots of the plug-in units 105 and 106. The wind speed sensor 3 represented in FIGS. 12A and 12B notably determines and/or measures a decrease in wind speed by pulling out the lower stage plug-in unit 106. In addition, regardless of the wind direction of the louver 2, the wind speed sensor 3 is arranged between the upper stage plug-in unit 105 and the louver board 2′a of the louver 2′ on the upper part of the shelf 1201 as a position which may recognize that the wind speed is lower than usual.

The shelf 1201 illustrated in FIGS. 12A and 12B is in a usual state where all the plug-in units 105 and 106 (and/or filler panels 108) are housed. In this usual state, the directions of the louver boards 2 a and 2′a of the louvers 2 and 2′ in the air blowing device are kept at a position to which the direction of ventilation by the fans 1 is directed, or kept in the usual directions, so that the inside of the shelf 1201 is in the optimum ventilation state. As illustrated in FIG. 12B, the usual directions of the louver boards 2 a and 2′a in the louvers 2 and 2′ are set in the vertical direction without inclination to allow wind from the fans 1 to move directly upward.

Hereinafter, the control of the louver boards 2 a and 2′a of the louvers 2 and 2′ when one of the upper stage plug-in units 105 is pulled out from the usual state illustrated in FIGS. 9A and 9B will be described. FIG. 13 is a diagram illustrating a case where the directions of the louver boards of the louvers 2 and 2′ are fixed. Furthermore, FIG. 14 illustrates the air blowing device according to the fourth embodiment.

In the case of FIG. 13, the louver boards 2 a and 2′a are kept in usual directions and left in the same directions even if the plug-in units 105 and/or 106 are unplugged.

In the case of FIG. 13, when the plug-in unit 105 in the upper stage is unplugged, an empty slot after unplugging becomes a path for wind to exit the shelf 1201. Thus, as illustrated by the dashed arrows in FIG. 13, wind exits from the shelf 1201 to the outside through the empty slot.

In this case, there is no influence on the amount of wind passing through the lower stage plug-in units 106. Rather, since ventilation resistance due to the presence of the plug-in unit 105 in the upper stage disappears, the amount of wind passing through the plug-in units 106 in the lower stage becomes comparatively favorable. Although the control of direction of the louver boards of the louvers 2 and 2′ may be made unnecessary when the plug-in unit 104 is removed, the direction of the louvers 2 and 2′ may be controlled as illustrated in FIG. 14.

In the case of the air blowing device of the fourth embodiment illustrated in FIG. 14, the directions of the louver boards 2 a and 2′a in the louvers 2 and 2′ are changed from the usual state when at least one of the upper-stage plug-in units 105 is pulled out of the upper stage. In other words, when the plug-in unit 105 is pulled out, the directions of the respective louver boards 2 a and 2′a in the louvers 2 and 2′ are changed so that the direction of ventilation by the fans 1 is changed to reduce the amount of wind exiting the shelf 1201 through the empty slot after unplugging.

In the case of FIG. 14, the direction along which the amount of wind flowing into the shelf 1201 through the empty slot is a direction along which the amount of wind drawn by the fans 1 passing through the vicinity of the back wiring board 102 in the interior of the shelf 1201 increases. In other words, as illustrated in FIG. 14, the directions of the louver boards 2 a and 2′a in the louvers 2 and 2′ are changed to directions inclined toward the interior of the shelf 1201.

Since the amount of wind is controlled as described above, a reduction in amount of air exiting the shelf from a front opening formed by the empty slot, is attainable.

The control of the louver boards of the louvers 2 and 2′ when one of the lower stage plug-in units 106 is pulled out from the usual state illustrated in FIGS. 12A and 12B will be described. FIG. 15 is a diagram illustrating a case where the directions of the louver boards of the louvers 2 and 2′ are fixed. Furthermore, FIG. 16 illustrates the air blowing device according to the fourth embodiment.

In the case of FIG. 15, the louver boards 2 a and 2′a are kept in usual directions and left in the same directions even if the plug-in units 105 and 106 are pulled out.

In the case of FIG. 15, when the plug-in unit 106 in the lower stage is pulled out, an empty slot after unplugging becomes the path of wind. Thus, part of the wind generated by the fans 1 exits the shelf 1201 via the empty slot.

As represented by the dashed arrows in FIG. 15, a large amount of wind escaping from the empty slot to the outside of the shelf 1201 may be generated. Thus, the amount of wind passing through the empty slot through the lower-stage plug-in units 106 and moving toward the upper-stage plug-in units 105 decreases. There is a disadvantage in that a decrease in the amount of wind may occur in the upper stage plug-in unit 105.

In the case of the air blowing device of the fourth embodiment illustrated in FIG. 16, the directions of the louver boards 2 a and 2′a in the louvers 2 and 2′ are changed from the usual state when at least one of the lower stage plug-in units 106 is pulled out of the lower stage. In other words, when the plug-in unit 106 is pulled out, the directions of the respective louver boards 2 a and 2′a in the louvers 2 and 2′ are changed so that the direction of ventilation by the fans 1 is changed to reduce the amount of wind exiting the shelf 1201 through the empty slot after unplugging.

In the case of FIG. 16, the direction along which the amount of wind exiting the shelf 1201 through the empty slot is decreased is a direction along which the amount of wind drawn by the fans 1 blowing to the back wiring board 102 in the interior of the shelf 1201 increases. As illustrated in FIG. 16, the directions of louver boards 2 a and 2′a in the louvers 2 and 2′ are changed to those inclined toward the interior of the shelf 1201.

By changing the direction of the louver boards 2 a and 2′a of these two louvers 2 and 2′, as illustrated by the dashed arrows in FIG. 16, the wind generated by the fans 1 blows in the direction opposite to the opening of the front side formed by the empty slot. Therefore, compared to the case of FIG. 15, the amount of wind exiting the shelf 1201 from the empty slot is reduced. As a result, compared to the case in FIG. 15, the amount of wind passing through the plug-in units 106 in the lower stage and heading to the plug-in units 105 in the upper stage increases. Therefore, the slope of thermal elevation in the plug-in unit 105 in the upper stage is reduced so that a duration time of a state where the slot is being emptied may be prolonged.

FIG. 17A and FIG. 17B are diagrams each illustrating a first exemplary configuration of a louver controller for controlling the directions of the above louver boards.

The louver controller of the first exemplary configuration includes: a biasing component 10 that biases the louver board 2 a in the usual direction; a direction-changing component 11 provided for each vertical line of the plug-in units 105 and 106, where the direction-changing component 11 is moved when the plug-in unit 106 is pulled out to change the direction of the louver boards 2 a from the usual direction against a biasing force of the biasing component 10; and a switching component 12 provided for each vertical line of the plug-in units 105 and 106, where the switching component 12 moves the direction-changing component 11 to an allowing position for allowing the louver board 2 a to be returned to the usual direction of the louver 2 a by the biasing force of the biasing component 10.

A top panel 112 of the upper portion of the shelf 1701 as illustrated in FIGS. 17A and 17B, inclines obliquely upward toward the back wiring board 102 and serves as a baffle part for sending out wind. Furthermore, fans 1 and a louver 2 included in an air blowing device are installed in a bottom panel 116 of the lower part of the shelf 1701. FIG. 17A is a schematic diagram viewed from the front side of the shelf 1701, and FIG. 17B is a schematic diagram viewed the right side of the shelf 1701. FIG. 17B is a diagram illustrating a state where the direction of each louver board 2 a of the louver 2 is changed from the usual state when one of the lower stage plug-in units 106 is pulled out.

The air blowing device illustrated in FIGS. 17A and 17B is of a push type where the fans 1 are installed on the lower part of the shelf 1701. For example, as in the case with FIGS. 4A and 4B, four fans 1 are arranged in line in the direction Y intersecting the direction X of plugging in/pulling out the plug-in units 105 and 106 and two fans 1 arranged in line in the plugging in/pulling out direction X. Furthermore, the louver 2 for controlling the direction of wind is placed above the fans 1.

For example, the louver 2 includes four louver boards 2 a in the width direction of the device. These louver boards 2 a are arranged in line and substantially parallel to one another in the plugging in/pulling out direction X and extending in the intersecting direction Y. As illustrated in FIG. 17B, the top plate 112 of the shelf 1701 is formed as an inclined baffle part. Therefore, the usual directions of the respective louver boards 2 a of the louver 2 are similar to those in FIGS. 4A and 4B and are inclined to the front side of the shelf 1701 in the depth direction thereof, or inclined in the direction of introducing wind from the fans 1 to the side opposite to the back wiring board 102 (FIG. 18C).

The details of the louver controller illustrated in FIGS. 17A and 17B will be described with reference to FIGS. 18A, 18B, and 18C, which illustrate the enlarged louver controller.

First, for example, the biasing component 10 may be a coil spring commonly provided for four louver boards 2 a and may provide all the louver boards 2 a with a biasing force (represented by the arrow M1 in FIG. 18A) that keeps them in the usual direction.

As illustrated in FIG. 17A, the direction-changing components 11 are independently formed on the respective slots of the lower stage plug-in units 106. Thus, the direction-changing components 11 of the respective slot operate individually. In the case of the louver controller illustrated in FIGS. 17A, 17B, and FIGS. 18A, 18B, and 18C, the direction-changing components 11 of each slot may, for example, include: sliding members 11 a in the form of a reversed U-shape and respectively arranged on four louver boards 2 a in the depth direction; and a biasing member 11 b that collectively biases the four sliding members 11 a. The four sliding members 11 a are connected to one another and slidable in the plugging in/pulling out direction and simultaneously biased by one biasing member 11 b. The biasing member 11 b may include a coil spring or the like and may provide the sliding members 11 a with a biasing force (represented by the arrow M2 in FIG. 18A) in the direction of changing the directions of the respective louver boards 2 a against the biasing force (represented by the arrow M1 in FIG. 8A) of the biasing component 10.

The switching component 12 is comprised of a L-shaped power point projection 12 a having a distal end protruding from a rail for guiding the lower stage plug-in unit 106, a linear working point projection 12 b that touches the back side of the direction-changing member 11 a; and a pivot 12 c that provides a connection between these projections and serves as a fulcrum. By pushing the power point projection 12 a by inserting a plug-in unit 106, the working point projection 12 b moves the sliding member 11 a against the biasing force (M2 in FIG. 18A) by the principle of leverage using the pivot 12 c as a fulcrum.

FIG. 18A illustrates a state of the louver controller when the lower stage plug-in unit 106 is pulled out. When the plug-in unit 106 is pulled out, the sliding members 11 a of the direction-changing components 11 are transferred to a direction-changing position by a biasing force of the biasing member 11 b to change the direction of the louver board 2 a which has been in the usual direction. By moving the direction-changing component 11, the direction of the louver board 2 a, which is pushed against one side wall of the sliding member 11 a, is changed to the direction, which has been described with reference to FIG. 7 or the like, against a biasing force of the biasing component 10. In addition, the movement of the direction-changing component 11 causes the switching component 12 to rotate around the pivot 12 c and the power point projection 12 a protrudes onto the rail.

FIG. 18B illustrates, for example, a state of a louver controller when two plug-in units 106 are pulled out of the lower stage and one of the plug-in units 106 is then inserted. In other words, the shelf 1701 is in a state where the plug-in unit 106 (not illustrated) which has been pulled out thus keeping the corresponding slot empty. FIG. 18B illustrates a case where one of the two plug-in units 106 is inserted into the slot.

For example, one unit is removed for maintenance among 8 plug-in units 106 of the lower stage shown in FIG. 17A, and FIG. 18B can also be said to be the state where the slot turned into an empty slot.

In the louver controller illustrated in FIG. 18B, the switching component 12 rotates around the pivot 12 c as the power point projection 12 a is pushed under the rail by inserting the plug-in unit 106. With rotation of the switching component 12, by using the pivot 12 c as a fulcrum, the working point projection 12 b pushes the sliding member 11 a so that the sliding member 11 a pushes back the biasing force of the biasing member 11 b and is moved from a direction changing position to an allowable position. The sliding member 11 a is transferred from the direction-changing position to an allowable position against a biasing force of the biasing member 11 b. The allowable position of the position-changing component 11 illustrated in FIG. 18B is a position where the louver board 2 a is allowed to return to the usual direction by a biasing force of the biasing component 10. In other words, the side wall of the sliding member 11 a, by which the louver board 2 a is pushed against the biasing force of the biasing component 10, moves away from the louver board 2 a. Thus, the louver board 2 a becomes rotatable between two opposite side walls of the sliding member 11 a.

Although the movement of the direction-changing component 11 to the allowable position allows the louver board 2 a to return to the usual direction, in the case of FIG. 18B, the direction-changing component 11 corresponding to the empty slot (not illustrated) keeps the state of FIG. 18A. Thus, the direction-changed state of the louver board 2 a is being kept as is.

In other words, among a plurality of slots on which the lower stage plug-in units 106 are mounted, the position of the direction-changing component 11 corresponding to an empty slot is the position represented in FIG. 18A. Furthermore, the position of another direction-changing component 11 corresponding to another slot, the slot on which the plug-in unit is mounted, is the position illustrated in FIG. 18B. Then, the louver boards 2 a covering all the slots are directed to introduce wind from below to the interior of the shelf (FIGS. 18A and 18B).

FIG. 18C illustrates a state of the louver controller when the last plug-in unit 106 is inserted, for example, after the state of FIG. 18B. Therefore, the insertion of all the plug-in units 106 is completed and the louver boards 2 a return to the usual direction.

In the louver controller illustrated in FIG. 18C, the power point projection 12 a is pushed under the rail by inserting the plug-in unit 106. The switching component 12 rotates around the pivot 12 c. The working point projection 12 b pushes the sliding member 11 a using the pivot 12 c as a fulcrum. The sliding member 11 a, which is pushed by the working point projection 12 b, is transferred from the direction-changing position to an allowable position against the biasing force of the biasing member 11 a. Since the direction-changing member 11 is in the allowable position, the side wall of the sliding member 11 a is detached from the louver boards 2 a. Thus, between two opposite side walls of the sliding member 11 a, the louver boards 2 a are allowed to return to the usual direction by the biasing force of the biasing member 10. In the case of FIG. 18C, unlike the case of FIG. 18B, there is no direction-changing component 11 that keeps the state of FIG. 18A. Thus, all the direction-changing components 11 are located at the allowable position in FIG. 18C, so that the louver board 2 a returns to the usual direction by accepting the biasing force of the biasing component 10.

Therefore, in the state where all the lower stage plug-in units 106 are mounted, the louver board 2 a is directed to introduce wind from below to the front side of the shelf (FIG. 18C).

Although the biasing component 10, the direction-changing component 11, and the switching component 12, which depend on the plugging in and unplugging of the lower stage plug-in unit 106, have been described above, the same configurations may be applied to the louver controller that depends on the plugging in and unplugging of the upper stage plug-in unit 105.

FIGS. 19A, 19B, and 19C are diagrams each illustrating a second exemplary configuration of the louver controller.

The louver controller according to the second exemplary configuration is an electric device that includes a detection component 20 and a direction-changing mechanism 21. The detection component 20 generates an electric signal when one or more of the plug-in units 105 and 106 are pulled out. The direction-changing mechanism 21 changes the direction of the louver boards 2 a in response to the electric signal from the detection component 20.

An air blowing device illustrated in FIGS. 19A and 19B is a push type like the device illustrated in FIGS. 17A and 17B, where the fans 1 are installed on the lower part of a shelf. For example, as in the case with FIGS. 4A and 4B, four fans 1 are arranged in line on the lower part of the shelf in the direction Y intersecting the direction X of plugging in/pulling out the plug-in units 105 and 106, and two fans 1 arranged in line in the plugging in/pulling out direction X. Furthermore, the louver 2 for controlling the direction of wind is placed above the fans 1. In the louver 2, four louver boards 2 a corresponding to the width of the device are arranged in line parallel to one another in the plugging in/pulling out direction X and extending in the intersecting direction Y. The usual direction of the louver boards 2 a in the louver 2 is the same as illustrated in FIGS. 4A and 4B and is inclined to the front side of the shelf. In other words, the usual direction of the louver board 2 a is the direction along which wind from the fans 1 is introduced to the side opposite to the back wiring board.

The detection component 20 is, for example, a switch which is turned on/off depending on the plugging in or unplugging of the lower stage plug-in unit 106. In other words, when the plug-in unit 106 is pulled out, the detection component 20 is turned off and does not generate any electric signal. When the plug-in unit 106 is completely plugged in, the detection component 20 is turned on and generates an electric signal. The detection component 20 illustrated in FIGS. 19A, 19B, and 19C is mounted in the vicinity of the inlet of a slot so that it is turned on to generate an electric signal every time the aforementioned filler panel is attached. For example, the detection component 20 may be mounted on the inlet of the slot and turned on in conjunction with a locking claw formed so that the locking claw catches and prevents the plug-in unit 105 or 106 from dropping when the plug-in unit 105 or 106 is inserted into the slot.

The direction-changing mechanism 21 includes a controller 21 a in which an electric signal from the detection component 20 is input, and a motor 21 b (for example, a stepping motor) to be driven by the controller 21 a. An output from the motor 21 b is simultaneously transmitted to the four louver boards 2 a through, for example, a rack-and-pinion 21 c and changes the directions of the louver boards 2 a.

The controller 21 a illustrated in FIGS. 19A, 19B, and 19C drives the motor 21 b and includes the function of a fan controller 22 that executes a revolving speed control of the fans 1. The fan controller 22 may be mounted together with the louver controller illustrated in FIGS. 17A and 17B and FIGS. 18A, 18B, and 18C.

FIG. 19A illustrates a state of the louver controller when the lower stage plug-in unit 106 is pulled out. When the plug-in unit 106 is unplugged, the detection component 20 is turned off. Then the controller 21 a of the direction-changing mechanism 21 drives the motor 21 b to change the direction of the louver board 2 a from the usual direction to the direction which has been described with reference to FIG. 7 or the like. Simultaneously, the fan controller 22 raises the rotation frequency of the fans 1 to cause an increase in the amount of wind blown into the shelf. An increase in the amount of wind due to an increased rotation frequency of the fans 1 leads to an increase in the amount of ventilation between the plug-in units 105 and 106. Thus, a cooling effect may be enhanced.

FIG. 19B illustrates a state of the louver controller where the lower stage plug-in unit 106 is being inserted partway. In FIG. 19B, the plug-in unit 106 is guided by a rail and is inserted in partway. In contrast, the detection component 20 mounted near the inlet of the slot is still in an OFF state. In other words, the detection unit 20 is turned on when the plug-in unit 106 is completely inserted into the slot without fault (for example, the connector of the plug-in unit is fit with the connector of the back wiring board). Thus, the detection unit 20 maintains an off state until the complete insertion of the plug-in unit 106 is attained. Since the detection component 20 maintains the off state, the direction-changing mechanism 21 does not act at this time. In addition, the revolving speed control of the fans 1 by the control unit 22 is also kept as is.

FIG. 19C is a diagram illustrating a state of the louver controller when the lower stage plug-in unit 106 is completely inserted. When the plug-in unit 106 is completely inserted, the detection component 20 is turned on. Then, an electric signal from the detection component 20 is input in the controller 21 a of the direction-changing mechanism 21. In response to the electric signal, the controller 21 a drives the motor 21 b and returns the louver boards 2 a to the usual direction through the rack-and-pinion 21 c. Subsequently, the fan controller 22, which is operated in conjunction with the controller 21 a, returns the rotation frequency of the fans 1 to a normal level and executes the revolving speed control of the fans 1 for normal times. In the present embodiment, the detection component 20 is provided for every slot. Therefore, the controller 21 a may adjust the direction of the louver boards 2 a to the usual direction (the state illustrated in FIG. 19C) when all the slot detection components 20 are turned on.

For example, the controller 21 a may include a hardware circuit, a combination of hardware, such as a CPU and a memory, and software, or a field programmable gate array (FPGA).

In addition to the above switch type, the detection component 20 may be one that outputs an electric signal when the connector of the plug-in unit 106 is fit to the connector of the back wiring board. In addition to the detection component 20, the direction-changing mechanism 21 may be able to control the direction of the louver board 2 a according to the output level of the wind speed sensor 3. Alternatively, the detection component 20 and the wind speed sensor 3 may be used together.

The detection component 20, the direction-changing mechanism 21, and the fan controller 22, which follow the plugging in/pulling out of the lower stage plug-in unit 106, have been described. Alternatively, the same configurations may be applied to the louver controller that follows the plugging in/pulling out of the upper stage plug-in unit 105.

FIGS. 20A, 20B, and 20C illustrate a third exemplary configuration of the louver controller.

The louver controller according to the third exemplary configuration includes a direction-changing mechanism 30 in which the motor 21 b and the rack-and-pinion 21 c in the direction-changing mechanism 21 illustrated in FIGS. 19A, 19B, and 19C are replaced with an electromagnet. Since the detection component 20 of the louver controller is the same as one illustrated in FIGS. 19A, 19B, and 19C, its duplicated description will be omitted. Other components of an air blowing device are similar to those illustrated in FIGS. 19A, 19B, and 19C. Thus, their duplicated descriptions will be omitted.

The direction-changing mechanism 30 includes a controller 30 a in which an electric signal from the detection component 20 is input, and an electromagnet 30 b which is driven by the controller 30 a. The electromagnet 30 b pulls an actuator, which is connected to and collectively operates the four louver boards 2 a by a magnetic force to change the directions of the louver boards 2 a. When the actuator 30 c is not pulled by the electromagnet 30 b, the louver board 2 a is biased by a biasing member 30 d, such as a coil spring, to keep the louver board in the usual direction.

The controller 30 a illustrated in FIGS. 20A, 20B, and 20C also includes the function of the fan controller 22 that controls the rotation frequency of the fans 1 in a manner similar to the controller 21 a illustrated in FIGS. 19A, 19B, and 19C.

FIG. 20A illustrates a state of the louver controller when the lower stage plug-in unit 106 is pulled out. When the plug-in unit 106 is unplugged, the detection component 20 is turned off. In response to this state, the controller 30 a of the direction-changing mechanism 30 generates a magnetic force by energizing the electromagnet 30 b. Since the electromagnet 30 b pulls the actuator 30 c by a magnetic force, the direction of the louver board 2 a is changed from the usual direction to the direction which has been described with reference to FIG. 7 or the like. At this time, simultaneously, the fan controller 22 raises the rotation frequency of the fans 1 to increase the amount of wind blown into the shelf.

FIG. 20B illustrates a state of the louver controller where the lower stage plug-in unit 106 is being inserted partway. In FIG. 20B, as in the case with FIG. 19B, the detection component 20 is still in an off state as described above. Since the detection component 20 maintains the off state, the direction-changing mechanism 30 does not act at this time. In addition, the revolving speed control of the fans 1 by the control unit 22 is also kept as is.

FIG. 20C is a diagram illustrating a state of the louver controller when the lower stage plug-in unit 106 is completely inserted. In this case, as in the case with FIG. 19C, the detection component 20 is turned on. Then, an electric signal from the detection component 20 is input in the controller 30 a of the direction-changing mechanism 30. In response to the electric signal, the controller 30 a blocks the energization of the electromagnet 30 b and turns off a magnetic force that has pulled the actuator 30 c. As a result the actuator 30 c becomes free and the louver board 2 a returns to the usual direction according to the biasing force of the biasing member 30 d.

Subsequently, the fan controller 22, which is operated in conjunction with the controller 30 a, returns the rotation frequency of the fans 1 to a normal level and executes the revolving speed control of the fans 1 for normal times. In the present embodiment, the detection component 20 is provided for every slot. Therefore, the controller 30 a may adjust the direction of the louver boards 2 a to the usual direction (the state illustrated in FIG. 20C) when all the slot detection components 20 are turned on.

For example, the controller 30 a may include a hardware circuit, a combination of hardware, such as a CPU and a memory, and software, or a field programmable gate array (FPGA).

In addition to the detection component 20, the direction-changing mechanism 30 may be able to control the direction of the louver board 2 a according to the output level of the wind speed sensor 3. Alternatively, the detection component 20 and the wind speed sensor 3 may be used together. The detection component 20, the direction-changing mechanism 30, and the fan controller 22, which follow the plugging in/pulling out of the lower stage plug-in unit 106, have been described. Alternatively, the same configurations may be applied to the louver controller that follows the plugging in/pulling out of the upper stage plug-in unit 105.

FIG. 21 illustrates an exemplary louver 2″ where the louver boards extending in the intersecting direction Y are divided for every slot of plug-in units 105 and 106. For example, the louver controller may include a direction-changing component 11 and a switching component 12, which are the same components as those illustrated in FIGS. 17A and 17B and FIGS. 18A, 18B, and 19C. However, the biasing component 10 illustrated in FIG. 21 is mounted on every line of louver boards 2″a.

Also in the case of an air blowing device illustrated in FIG. 21, a louver controller operates in a manner similar to one illustrated in FIGS. 18A, 18B, and 18C. In the case of FIG. 21, however, the directions of the lines of the louver boards 2″a are individually controlled. The direction of the line of the louver boards 2″a from which an empty slot is generated is only changed from the usual direction. Therefore, a good ventilation state for each slot may be realized depending on the housing state of the plug-in units 105 and 106 (and the filler panel 108) in each slot.

All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. 

What is claimed is:
 1. An air blowing device comprising: a fan mounted on at least one of an upper part and a lower part of a shelf; a louver having a louver board that extends in a direction intersecting with a direction of plugging in of a plug-in unit; and a louver controller to control the direction of the louver board based on a change of a mounting status of plug-in unit housed in a shelf.
 2. The air blowing device according to claim 1, further comprising: a fan controller to control an increase in rotation frequency of the fan based on a change of the mounting status of plug-in units housed in the shelf.
 3. The air blowing device according to claim 1, wherein the louver board is divided for every slot of the plug-in units.
 4. The air blowing device according to claim 1, wherein the louver controller includes: a biasing component to bias the louver board to a usual direction; a direction-changing component to change the direction of the louver board from the usual direction by moving when a plug-in unit is removed from the shelf, where the direction-changing component is provided for every slot of the plug-in units housed in the shelf; and a switching component to move the direction-changing component to an allowable position where returning the direction of the louver board to the usual direction is allowed when the plug-in unit is inserted, where the switching component is provided for every slot of the plug-in units housed in the shelf.
 5. The air blowing device according to claim 4, the direction-changing component includes; a U-shaped sliding member that moves in the plugging in direction when the plug-in unit is removed, and one side wall of the sliding member changes the direction of the louver board to the usual direction by pushing the louver board; and the switching component includes; a power point projection and a working point projection which are connected to each other through a pivot that serves as a fulcrum, where the power point projection is pushed by insertion of the plug-in unit to cause the working point projection to move the sliding member to the allowable position using the pivot as a fulcrum.
 6. The air blowing device according to claim 1, wherein the louver controller includes: a detection component to generate an electric signal when detecting that one or more of plug-in units housed in the shelf is removed; and a direction-changing component to change the direction of the louver board in response to the electric signal.
 7. The air blowing device according to claim 6, wherein the direction-changing component includes: a motor controller to receive the electric signal from the detection component; and a motor to change the direction of the louver board when the motor is driven by the motor controller.
 8. The air blowing device according to claim 6, wherein the direction-changing component includes; an electromagnet controller to receive the electric signal from the detection component; and an electromagnet to change the direction of the louver board when the electromagnet is driven by the electromagnet controller.
 9. The air blowing device according to claim 6, wherein the direction-changing component changes the direction of the louver board based on a wind speed sensor to detect a wind velocity within the shelf.
 10. The air blowing device according to claim 1, wherein the louver controller includes: a wind speed sensor to detect a wind velocity within the shelf; and a direction-changing component to change the direction of the louver board in response to an output level of the wind speed sensor.
 11. The air blowing device according to claim 1, wherein the louver controller includes: a detection component to generate an electric signal when a connector of the plug-in unit is fit to a connector of a back wiring board of the shelf; and a direction-changing component to change the direction of the louver board in response to the electric signal. 